<template>

  <div class="app-container">

    <h2 style="text-align: center;">发布新课程</h2>

    <el-steps :active="1" process-status="wait" align-center style="margin-bottom: 40px;">
      <el-step title="填写课程基本信息"/>
      <el-step title="创建课程大纲"/>
      <el-step title="最终发布"/>
    </el-steps>

    <el-form label-width="120px">

        <el-form-item label="课程标题">
            <el-input v-model="courseInfo.title" placeholder=" 示例：机器学习项目课：从基础到搭建项目视频课程。专业名称注意大小写"/>
        </el-form-item>

        <!-- 所属分类 TODO -->
        <el-form-item label="课程分类">
            <el-select
                v-model="courseInfo.subjectParentId"
                placeholder="一级分类" @change="subjectLevelOneChanged">

                <el-option
                    v-for="subject in subjectOneList"
                    :key="subject.id"
                    :label="subject.title"
                    :value="subject.id"/>

            </el-select>

            <!-- 二级分类 -->
            <el-select v-model="courseInfo.subjectId" placeholder="二级分类">
                <el-option
                    v-for="subject in subjectTwoList"
                    :key="subject.id"
                    :label="subject.title"
                    :value="subject.id"/>
            </el-select>
        </el-form-item>        

        <!-- 课程讲师 TODO -->
        <el-form-item label="课程讲师">
          <el-select
              v-model="courseInfo.teacherId"
              placeholder="请选择">

              <el-option
                  v-for="teacher in teacherList"
                  :key="teacher.id"
                  :label="teacher.name"
                  :value="teacher.id"/>

          </el-select>
        </el-form-item>

        <el-form-item label="总课时">
            <el-input-number :min="0" v-model="courseInfo.lessonNum" controls-position="right" placeholder="请填写课程的总课时数"/>
        </el-form-item>

        <!-- 课程简介 TODO -->
        <el-form-item label="课程简介">
            <tinymce :height="300" v-model="courseInfo.description"/>
        </el-form-item>

        <!-- 课程封面 TODO -->
        <el-form-item label="课程封面">

            <el-upload
                :show-file-list="false"
                :on-success="handleAvatarSuccess"
                :before-upload="beforeAvatarUpload"
                :action="BASE_API+'/eduOss/fileOss'"
                class="avatar-uploader">
                <img :src="courseInfo.cover">
            </el-upload>

        </el-form-item>

        <el-form-item label="课程价格">
            <el-input-number :min="0" v-model="courseInfo.price" controls-position="right" placeholder="免费课程请设置为0元"/> 元
        </el-form-item>

        <el-form-item>
            <el-button :disabled="saveBtnDisabled" type="primary" @click="saveOrUpdate">保存并下一步</el-button>
        </el-form-item>
    </el-form>
  </div>
</template>
<script>
import course from '@/api/edu/course'
import subject from '@/api/edu/subject'
import Tinymce from '@/components/Tinymce'

export default {
  components: { Tinymce },
  data() {
    return {
      saveBtnDisabled: false, // 保存按钮是否禁用
      BASE_API: process.env.BASE_API, // 接口API地址
      courseInfo:{
            title: '',
            subjectId: '',
            subjectParentId:'',//一级分类id
            teacherId: '',
            lessonNum: 0,
            description: '',
            cover: '/static/10.jpg',
            price: 0
      },
      courseId:"",
      teacherList:[],
      subjectOneList:[],
      subjectTwoList:[],
    }
  },

  created() {
    if(this.$route.params && this.$route.params.id){
        this.courseId = this.$route.params.id
        this.getCourseInfo()
    }else{
      this.courseInfo = {}
      this.courseInfo.cover = '/static/10.jpg'
      this.findAllTeacher()
      this.findAllSubject()
    }

  },

  methods: {
      //根据课程id查询课程信息
      getCourseInfo(){
        course.getCourseInfo(this.courseId)
          .then(response =>{
            this.courseInfo = response.data.courseInfoVo
            //根据id查询一级分类和二级分类
            subject.findAllSubject()
              .then(response =>{
                this.subjectOneList = response.data.list
                //遍历所有一级分类
                for(let i=0;i<this.subjectOneList.length;i++){
                  var oneSubject = this.subjectOneList[i];
                  if(this.courseInfo. subjectParentId == oneSubject.id){
                    this.subjectTwoList = oneSubject.children
                  }
                }
              })
          })
      },
      //上传封面成功调用的方法
        handleAvatarSuccess(res, file) {
            this.courseInfo.cover = res.data.url
        },
        //上传之前调用的方法
        beforeAvatarUpload(file) {
            const isJPG = file.type === 'image/jpeg'
            const isLt2M = file.size / 1024 / 1024 < 2

            if (!isJPG) {
                this.$message.error('上传头像图片只能是 JPG 格式!')
            }
            if (!isLt2M) {
                this.$message.error('上传头像图片大小不能超过 2MB!')
            }
            return isJPG && isLt2M
        },    
    findAllSubject(){
      subject.findAllSubject()
        .then(response => {
          this.subjectOneList = response.data.list
        })
    },
    subjectLevelOneChanged(value){
      this.courseInfo.subjectId = ''
      for(var i=0;i<this.subjectOneList.length;i++){
        var oneSubject = this.subjectOneList[i]
        if(value == oneSubject.id){
          this.subjectTwoList = oneSubject.children
          
        }
      }
    },
    findAllTeacher(){
      course.findAllTeacher()
        .then(response =>{
          this.teacherList = response.data.list
        })
    },
    //添加课程信息
    addCourseInfo(){
      course.addCourseInfo(this.courseInfo)
                  .then(response =>{
                      //提示信息
                      this.$message({
                          type:'success',
                          message:'添加课程信息成功'
                      })
                      //跳转
                      this.$router.push({ path: '/edu/course/chapter/'+response.data.courseId })
                  })
      
    },
    //修改课程信息
    updateCourseInfo(){
      course.updateCourseInfo(this.courseInfo)
                  .then(response =>{
                      //提示信息
                      this.$message({
                          type:'success',
                          message:'修改课程信息成功'
                      })
                      //跳转
                      this.$router.push({ path: '/edu/course/chapter/'+this.courseId })
                  })
      
    },
    saveOrUpdate() {
      if(!this.courseId){
        this.addCourseInfo()
      }else{
        this.updateCourseInfo()
      }
        
    }
  }
}
</script>